HydrogenAudio

Lossy Audio Compression => Other Lossy Codecs => Topic started by: chanakyasun on 2011-02-01 05:41:57

Title: .ac3 and .dts
Post by: chanakyasun on 2011-02-01 05:41:57

How will be the structure of files with extention .ac3 , .dts , .dtshd?

How is the Metadata (artist , trach, album) stored in these formats?

are there any special container formats for .ac3 and .dts? 


I found information telling about dolby digital .....

I need overview on these audio formats Pls



Regards
Title: .ac3 and .dts
Post by: saratoga on 2011-02-01 05:53:48
I think they're just raw compressed audio streams.  I don't think either is widely tagged, although its possible something out there can stick ID3 tags on them.
Title: .ac3 and .dts
Post by: chanakyasun on 2011-02-01 06:50:53
I think they're just raw compressed audio streams.  I don't think either is widely tagged, although its possible something out there can stick ID3 tags on them.


if they're just raw compressed audio streams , i have doubt as following
there are different dolby digital or dts audio techiniques like dolby digital plus, dts-es, dts-master audioHD ...
how will we know that the content in side the audio file.
How different are these audio formats?
Title: .ac3 and .dts
Post by: mjb2006 on 2011-02-01 07:19:49
May I suggest doing some simple web searches? For relatively non-technical comparisons of AC-3 and DTS, try searching for "ac-3 dts comparison (http://www.google.com/search?q=ac-3+dts+comparison)".

For technical details about each of the formats, here is what I did:

1. I searched for "AC-3" in Google.
2. I clicked on one of the top results: the Wikipedia article on Dolby Digital.
3. I skimmed the article and noticed at the bottom there was a link to the standard (http://www.atsc.org/cms/index.php/standards/published-standards/48-atsc-a52-standard). I clicked on it. I arrived at a site that had a PDF of the standard.

As for DTS, that standard is not available for free. However, with a search for "open-source DTS decoder" (http://www.google.com/search?q=open-source+DTS+decoder), you can find open-source DTS (and AC-3!) decoder software which you could study and learn from. e.g. libdts, libdca, and AC3Filter.
Title: .ac3 and .dts
Post by: saratoga on 2011-02-01 16:12:49
how will we know that the content in side the audio file.


I don't think you do until you decode it.  But no one uses raw streams so its not an issue.  They're always in some other container.

How different are these audio formats?


Rather different.  AC3 is a conventional if extremely primitive MDCT encoder like AAC or Vorbis.  DTS is a subband coder like MP2 or MPC.  DTS-AudioHD or whatever they call it is (IIRC) a hybrid lossy/lossless codec more like wavpack.
Title: .ac3 and .dts
Post by: benski on 2011-02-01 17:17:08
Quote
How will be the structure of files with extention .ac3 , .dts , .dtshd?

as bitstreams, according to the spec

Quote
How is the Metadata (artist , trach, album) stored in these formats?

it's not

Quote
are there any special container formats for .ac3 and .dts?

there are other containers which often contain them, like AVI, MPEG-2 Transport Stream, MPEG-2 Program Stream, Matroska, MP4 (as private streams) and WAV/AIFF, amongst many many others.  These container formats can contain many other things, also.
Title: .ac3 and .dts
Post by: chanakyasun on 2011-02-02 07:09:43
How is the Metadata (artist , trach, album) stored in these formats?

Is it possible to embedd ID3 tags in .dts or .ac3 formats?

Thanks and Regards 
Title: .ac3 and .dts
Post by: Kohlrabi on 2011-02-02 08:20:03
A possible solution is to mux AC3 or DTS into Matroska (http://www.bunkus.org/videotools/mkvtoolnix/). Good audio players should be able to handle MKV/MKA and read metadata from these files.